Cobra cytotoxins: structural organization and antibacterial activity

Cardiotoxins (cytotoxins, CT) are β-structured proteins isolated from the venom of cobra. They consist of 59-61 amino acid residues, whose antiparallel chains form three 'fingers'. In contrast to neurotoxins with an overall similar fold, CTs are amphiphilic. The amphiphilicity is caused by positively charged lysine and arginine residues flanking the tips of the loops that consist primarily of hydrophobic amino acids. A similar distribution of amino acid residues is typical for linear (without disulfide bonds) cationic cytolytic peptides from the venoms of other snakes and insects. Many of them are now considered to be lead compounds in combatting bacterial infections and cancer. In the present review, we summarize the data on the antibacterial activity of CTs and compare it to the activity of linear peptides.